phase29an(p11): populate exitmap presence from exit usage

src/mir/builder/control_flow/plan/facts/feature_facts.rs

@@ -44,9 +44,24 @@ pub(in crate::mir::builder) fn try_extract_loop_feature_facts(
     for stmt in body {
         update_exit_usage_from_stmt(stmt, &mut exit_usage);
     }
+    let mut kinds_present = BTreeSet::new();
+    if exit_usage.has_return {
+        kinds_present.insert(ExitKindFacts::Return);
+    }
+    if exit_usage.has_break {
+        kinds_present.insert(ExitKindFacts::Break);
+    }
+    if exit_usage.has_continue {
+        kinds_present.insert(ExitKindFacts::Continue);
+    }
+    let exit_map = if kinds_present.is_empty() {
+        None
+    } else {
+        Some(ExitMapFacts { kinds_present })
+    };
     Ok(LoopFeatureFacts {
         exit_usage,
-        exit_map: None,
+        exit_map,
         value_join: None,
         cleanup: None,
     })
@@ -80,7 +95,7 @@ fn update_exit_usage_from_stmt(stmt: &ASTNode, usage: &mut ExitUsageFacts) {
 
 #[cfg(test)]
 mod tests {
-    use super::{try_extract_loop_feature_facts, ExitUsageFacts};
+    use super::{try_extract_loop_feature_facts, ExitKindFacts, ExitUsageFacts};
     use crate::ast::{ASTNode, LiteralValue, Span};
 
     fn lit_bool(value: bool) -> ASTNode {
@@ -117,7 +132,11 @@ mod tests {
                 has_return: true,
             }
         );
-        assert!(facts.exit_map.is_none());
+        let exit_map = facts.exit_map.expect("exit_map");
+        assert_eq!(exit_map.kinds_present.len(), 3);
+        assert!(exit_map.kinds_present.contains(&ExitKindFacts::Return));
+        assert!(exit_map.kinds_present.contains(&ExitKindFacts::Break));
+        assert!(exit_map.kinds_present.contains(&ExitKindFacts::Continue));
     }
 
     #[test]